Judgment This study was done in order to evaluate the effectiveness of the revisions made in the course of medical ethics for undergraduate medical students. Medical Students of Tehran University of Medical Sciences who took the course of medical ethics in a semester before the implementation of the revision and those who took the course after the implementation of the revision at the beginning and at the end of course responded to two questionnaires (one for evaluating knowledge and the other for assessing their moral judgment). Response rate was between 70 to 93.1 percent. Students’ knowledge was significantly higher in the semester after the course revision (mean ± SD: 6.12 ± 1.3) in comparison with the semester before the reform (mean ± SD: 3.63 ± 1.7) (P=0.001). Students’ knowledge after taking this course showed an increase of about 60% when compared with their knowledge level before starting the course (P=0.001). There was no significant difference in the level of moral judgment before and after taking the revised course of medical ethics while moral judgment level of students in two semester[before (21.21 ± 4.0) and after 15.25 ± 2.87) reform] were significantly different (P=0.02). The revisions made in the course of medical ethics for medical students were effective in improving students’ knowledge but could not improve their moral judgment. This could be due to the short length of this course and also the small sample size in this study. We suggest that this study should be repeated with larger sample size and also with other methods of a course evaluation.